Variable cam timing phaser

Abstract

A variable cam timing phaser includes a housing and a rotor defining a plurality of chambers, a first end plate and a second end plate. The variable cam timing phaser additionally includes at least one air vent located at a center of a region of rotation of at least one of the housing, the rotor, the first end plate, or the second end plate. At least one air vent is fluidly coupled to the plurality of chambers and configured to exhaust air from the plurality of chambers. The variable cam timing phaser also includes a reservoir fluidly coupled to the at least one air vent. The reservoir is configured to hold a hydraulic fluid and to reduce air from being absorbed through the at least one air vent and into the plurality of chambers.

Description

[0001] CROSS-REFERENCE TO RELATED APPLICATIONS This application claims priority to U.S. Patent Application No. 18 / 388,982, filed on November 13, 2023, the entire contents of which are incorporated herein by reference in their entirety. Technical Field

[0002] The present invention generally relates to a variable cam timing phaser and a variable cam timing system including the variable cam timing phaser. Background Art

[0003] In an automobile, an internal combustion engine (ICE) uses one or more camshafts to open and close intake and exhaust valves by selectively actuating valve stems in response to cam lobes as the camshaft(s) rotate and overcome the force of valve springs, which maintain the valve seats. The shape and angular position of the cam lobes can affect the operation of the ICE. In the past, the angular position of the camshaft was fixed relative to the angular position of the crankshaft. But now it is possible to use variable camshaft timing (VCT) technology to vary the angular position of the camshaft relative to the crankshaft. VCT technology can be implemented using a VCT device (sometimes called a camshaft phaser), which changes the angular position of the camshaft relative to the crankshaft. These camshaft phasers are usually hydraulically actuated.

[0004] A variable cam timing phaser typically includes a housing, a rotor, inner and outer plates, and a control valve, among other possible components. Hydraulic fluid in the form of oil is sent into and out of chambers defined by the housing, the rotor, and a plurality of plates to perform the advance and retard functions of the variable cam timing phaser. The control valve works to manage the oil as it flows into and out of the chambers, and manages the oil in response to commands from an engine control unit (ECU).

[0005] In recent years, there has been a desire to limit the air introduced into the chamber, which is defined by the housing and the rotor. However, current variable cam timing phasers are unable to limit the air introduced into the chamber. For this reason, there is still a need for an improved variable cam timing phaser. Summary of the invention

[0006] A variable cam timing phaser of a variable cam timing system, wherein the variable cam timing system includes a camshaft, the variable cam timing phaser includes a housing, the housing has a housing wall, the housing wall is arranged around an axis, and the housing defines the interior of the housing. The housing has a first housing side and a second housing side, the first housing side faces a first direction along the axis, and the second housing side faces a second direction opposite to the first direction. The variable cam timing phaser also includes a rotor, which is arranged inside the housing and is movable relative to the housing. The rotor has a hub and a plurality of blades, and the blades extend from the hub away from the axis toward the housing wall. The rotor and the housing define a plurality of chambers, wherein each of the plurality of chambers has an advance chamber and a delay chamber. The variable cam timing phaser further includes a first end plate and a second end plate, the first end plate is coupled to the first housing side and further defines a plurality of chambers, and the second end plate is coupled to the second housing side and further defines a plurality of chambers. In addition, the variable cam timing phaser includes at least one air vent, and the air vent is located at the center of the rotation area of ​​at least one of the housing, the rotor, the first end plate, or the second end plate. The center of the rotational area is defined relative to the rotational movement of the variable cam timing phaser assembly. During use of the variable cam timing phaser, air brought to the center of the rotational area and received in at least one air vent escapes the hydraulic fluid, and the hydraulic fluid is retained in the variable cam timing phaser. At least one air vent is fluidly connected to a plurality of chambers and is configured to exhaust air from the plurality of chambers. At least one air vent is defined by at least one of the rotor, the first end plate, the second end plate, and the housing. The variable cam timing phaser also includes a reservoir, which is fluidly connected to the at least one air vent. The reservoir is configured to hold hydraulic fluid and is configured to reduce air being absorbed (ingest) through the at least one air vent and entering the plurality of chambers. BRIEF DESCRIPTION OF THE DRAWINGS

[0007] Other advantages of the present disclosure will be readily appreciated as they become better understood by reference to the following detailed description when considered in conjunction with the accompanying drawings.

[0008] Figure 1 is a front view of a variable cam timing phaser comprising a housing, a first end plate, and at least one air vent, wherein the air vent is defined by the first end plate; Figure 2 yes Figure 1 a front view of a variable cam timing phaser of , wherein the first end plate is transparent for purposes of illustration, and wherein the variable cam timing phaser includes a rotor, wherein the housing and the rotor define a plurality of chambers; Figure 3is a rear view of a variable cam timing phaser, the variable cam timing phaser further comprising a second end plate, and wherein at least one air vent is defined by the second end plate; Figure 4 yes Figure 3 A rear view of a variable cam timing phaser, wherein the second end plate is transparent for illustration purposes; Figure 5 is a rear view of a variable cam timing phaser, wherein at least one air vent is defined by a rotor; Figure 6 yes Figure 5 A rear view of a variable cam timing phaser of the embodiment of the present invention, wherein the rotor is partially transparent for illustration purposes; Figure 7 Depicted Figure 5 A front view of a variable cam timing phaser; Figure 8 depicts a perspective view of a variable cam timing phaser wherein at least one air vent is in the form of a gap between a second end plate and a rotor; Fig. 9 depicts a perspective view of a variable cam timing phaser wherein at least one air vent is in the form of a gap between a first end plate and a rotor; Fig.10 depicts a perspective view of a variable cam timing phaser wherein at least one air vent is in the form of a gap between a first end plate and a rotor; Fig.11 Depicted Fig.10 A variable cam timing phaser, wherein the first end plate is partially transparent for illustrative purposes; Fig. 12A is a cross-sectional view of a variable cam timing phaser, the variable cam timing phaser further comprising a ring coupled to the first end plate, wherein the ring defines a reservoir, and the first end plate defines an air vent; Fig. 12B yes Fig. 12A A top view of the ring, air vents and storage portion; Fig.13A yes Fig. 12A a cross-sectional view of another embodiment of a ring of wherein the reservoir has a first ring cross-sectional flow area and a second ring cross-sectional flow area, and wherein the second ring cross-sectional flow area is less than the first ring cross-sectional flow area; Fig. 13B yes Fig.13A A top view of the ring, air vents and storage portion; Fig.14is a top view of the ring, air vents and storage portion, wherein the storage portion is defined 360 degrees about an axis of the house; Fig.15A is a cross-sectional view of another embodiment of a variable cam timing phaser, wherein the first end plate defines a reservoir, and the rotor defines an air vent; Fig. 15B yes Fig.15A A top view of a rotor, a first end plate, a storage portion and a rotor; Fig.16A is a cross-sectional view of another embodiment of a variable cam timing phaser, wherein the reservoir is defined by a first end plate and a rotor, and wherein the air vent is defined by the first end plate; Fig. 16B yes Fig.16A A top view of the rotor, the first end plate, the storage portion and the air vent; Fig.17A is a cross-sectional view of another embodiment of a variable cam timing phaser, wherein the reservoir is defined by a rotor and the air vent is defined by the rotor; Fig. 17B yes Fig.17A A top view of a rotor, a first end plate, a second end plate, a storage portion, and an air vent; Fig.18 is a cross-sectional view of another embodiment of a variable cam timing phaser, wherein the first end plate has an end plate protrusion extending away from the second end plate, wherein the end plate protrusion defines a reservoir, and wherein the first end plate defines an air vent; Fig.19 is a cross-sectional view of another embodiment of a variable cam timing phaser, wherein the rotor has a rotor protrusion extending away from the second end plate, and wherein the rotor protrusion defines a reservoir, and the rotor defines an air vent; and Fig. 20 is a side cross-sectional view of a variable cam timing system including a variable cam timing phaser, a camshaft, and a control valve. DETAILED DESCRIPTION

[0009] Referring to the drawings, wherein like numerals represent like components throughout the several views, a variable cam timing phaser 30 is generally Figure 1-11 As shown in Fig. 20 As shown in FIG. 1 , the variable cam timing system 32 may include a variable cam timing phaser, wherein the variable cam timing system 32 also includes a camshaft 34. Figure 1-11As shown in FIG. 1 , the variable cam timing phaser 30 includes a housing 36 having a housing wall 38 disposed about an axis A and defining a housing interior 40. The housing 36 has a first housing side 42 and a second housing side 44, as shown in FIG. Figure 1 , 2 , 7-10, the first housing side 42 faces the first direction along the axis A, as shown in Figure 3-6 As shown in Figures 8-11, the second housing side surface 44 faces a second direction opposite to the first direction. The variable cam timing phaser 30 also includes a rotor 46 disposed within the housing interior 40 and movable relative to the housing 36. The rotor 46 has a hub 48 and a plurality of vanes 50 extending from the hub 48 away from the axis A toward the housing wall 38. The rotor 46 and the housing 36 define a plurality of chambers 52, wherein each of the plurality of chambers 52 has an advance chamber 54 and a retard chamber 56, as shown in Figures 8-11. Figure 2 The hub 48 may define a plurality of ports 51, such as Figure 6 as shown in .

[0010] The variable cam timing phaser 30 also includes a first end plate 58 coupled to the first housing side 42 and further defining the plurality of chambers 52 and a second end plate 60 coupled to the second housing side 44 and further defining the plurality of chambers 52. It will be appreciated that in the context of the present disclosure, the first end plate 58 may be integral (i.e., one piece) with the housing 36 when the first end plate 58 is coupled to the first housing side 42, or the first end plate 58 may be a separate component from the housing 36. Similarly, it will be appreciated that in the context of the present disclosure, the second end plate 60 may be integral (i.e., one piece) with the housing 36 when the second end plate 60 is coupled to the second housing side 44, or the second end plate 60 may be a separate component from the housing 36. Additionally, the variable cam timing phaser 30 includes at least one air vent 62 located at a center 64 of a rotational region of at least one of the housing 36, the rotor 46, the first end plate 58, or the second end plate 60. The center of rotation area 64 is defined relative to the rotational movement of the variable cam timing phaser 30. For example, the center of rotation area 64 can be relative to the rotational movement of the first end plate 58 and its positional relationship to the hub 48, and Figure 14 is approximated and represented by the dotted circle depicted in . The center 64 of the rotating area can coincide with the radially inner area of ​​the chamber 52 and can be located near the hub 48 of the rotor 46. At the center 64 of the rotating area, air removal and purification of the air are effective and efficient. In addition, at least one air vent 62 and a plurality of air vents 62 can be located at a corner or corner area of ​​the chamber 52. For example, a single air vent 62 can be located at each corner of each of the chambers 52. In addition, in some embodiments, relative to the specific position of the air vent 62 on the first end plate 58, the air vent 62 can be located at a circumferential and radial position to be in fluid communication with the established fluid chamber 52.

[0011] During use of the variable cam timing phaser 30, air can be brought to the center 64 of the rotational area by escaping hydraulic fluid and received in at least one air vent 62, and liquid is retained in the variable cam timing phaser 30. The at least one air vent 62 is fluidly coupled to the plurality of chambers 52 and is configured to exhaust air from the plurality of chambers 52. The at least one air vent 62 is defined by at least one of the rotor 46, the first end plate 58, the second end plate 60, and the housing 36. In one embodiment, the at least one air vent 62 is in direct fluid communication with the plurality of chambers 52. A description of the at least one air vent can be found in U.S. Pat. No. 11,168,591, the disclosure of which is incorporated by reference in its entirety.

[0012] At least one air vent 62 may be fluidly coupled to the advance chamber 54, or at least one air vent 62 may be fluidly coupled to the retard chamber 56. It will be appreciated that the variable cam timing phaser 30 may have two or more air vents 62, with each air vent associated with one chamber 52, and more typically, two air vents 62 are associated with each chamber 52. In one embodiment, as shown in FIG. Figure 8-11 As shown in FIG. 8 , the at least one air vent 62 is further defined as at least one gap 65 defined between at least one of the first end plate 58 or the second end plate 60 and the hub 48 of the rotor 46 .

[0013] In addition, refer to Figure 12A-19, the variable cam timing phaser 30 includes a reservoir 66 that is fluidly coupled to at least one air vent 62. The reservoir 66 can be configured to be at or near atmospheric pressure. It will be understood that atmospheric pressure can refer to the pressure inside the crankcase of the internal combustion engine, or can be the pressure of ambient air. The reservoir 66 is configured to hold hydraulic fluid and is configured to reduce air being absorbed through at least one air vent 62 and entering the plurality of chambers 52. The variable cam timing phaser 30 including the reservoir 66 provides several advantages. First, the reservoir 66 holds hydraulic fluid during operation of the variable cam timing phaser 30, during which the variable cam timing phaser 30 spins around the axis A. Typically, this hydraulic fluid comes from leakage of hydraulic fluid from the air vent 62 to the active chamber (either the advance chamber 54 or the retard chamber 56). During the rotation of the variable cam timing phaser 30, the at least one air vent 62 vents into the reservoir 66, rather than communicating directly with the atmosphere. The reservoir 66 is typically in communication with, i.e., fluidly coupled to, the at least one air vent 62 at its maximum radius from the axis A, and the reservoir 66 is typically in communication with, i.e., fluidly coupled to, the atmosphere at its minimum radius from the axis A. During most operating speeds, the centripetal acceleration is greater than the acceleration due to gravity, which then allows the reservoir 66 to retain hydraulic fluid. In addition, during the rotation of the variable cam timing phaser 30, the primary buoyancy force acting on any air bubbles in the reservoir is toward the axis A. At the same time, since the density of the air bubbles is lower than that of the hydraulic fluid, the hydraulic fluid in the reservoir 66 will cause any air bubbles to move toward the central axis A. As the air is pushed out of the active chamber (either the advance chamber 54 or the retard chamber 56), the air is forced to escape through the air vent 62 into the reservoir 66. As air moves into reservoir 66 , it tends to move toward axis A and away from air vent 62 , which causes variable cam timing phaser 30 to be more likely to draw oil rather than air from reservoir 66 during low pressure events where the pressure in the active chambers of advance chamber 54 and retard chamber 56 is lower than atmospheric pressure, such as the pressure in the crankcase or the pressure of the ambient air.

[0014] The variable cam timing phaser 30 may not have a check valve disposed in the air vent 62. In one embodiment, the variable cam timing phaser 30 does not have a mechanical check valve that moves between an open position for allowing air and hydraulic fluid to flow through the air vent 62 and a closed position for restricting air and hydraulic fluid from flowing through the air vent 62.

[0015] like Figure 12A-14As shown, the variable cam timing phaser 30 can further include a ring 68 coupled to the first end plate 58, wherein the ring 68 defines a reservoir 66, and optionally, the ring 68 and the first end plate 58 define the reservoir 66. The reservoir 66 can be machined into the ring 68. As the hydraulic fluid and air are pushed out of the active chamber (either the advance chamber 54 or the retard chamber 56), both the hydraulic fluid and the air can flow into the reservoir 66. Centrifugal force will tend to trap the hydraulic fluid in the reservoir 66, while the air (such as air bubbles) tends to move toward the axis A due to its lower density than the hydraulic fluid. The reservoir 66 can be fluidly coupled to the atmosphere, which allows the air to evacuate into the atmosphere and allows the hydraulic fluid to flow into the chamber 52 during a low pressure event, in which the pressure in the active chamber of the advance chamber 54 and the retard chamber 56 is lower than atmospheric pressure, such as the pressure in the crankcase or the pressure of the ambient air, rather than drawing air back into the chamber 52. In Figure 12A-14 In the embodiment shown in FIG. 8 , the first end plate 58 may define at least one air vent 62 .

[0016] like Fig.13A As shown in FIG. 1 , the reservoir 66 has a first ring cross-sectional flow area 70 and a second ring cross-sectional flow area 72, wherein the second ring cross-sectional flow area 72 is smaller than the first ring cross-sectional flow area 70. If the centrifugal force decreases to a point where the hydraulic fluid is drained from the reservoir 66, making the second ring cross-sectional flow area 72 smaller than the first ring cross-sectional flow area 70 increases the time required to drain the reservoir 66. When the ring 68 and the first end plate 58 define the reservoir 66, the reservoir 66 can be defined 360 degrees around the axis A, as shown in FIG. Fig.14 In such an embodiment, the at least one air vent 62 is further defined as a plurality of air vents 62, and each of the air vents 62 is fluidly coupled to the plurality of chambers 52 and configured to exhaust air from the plurality of chambers 52. Then, during operation of the variable cam timing phaser 30, the air vents 62 all exhaust air into a reservoir 66, which is defined 360 degrees around the axis A.

[0017] In another embodiment, Fig.15A and 15BAs shown in , the first end plate defines a reservoir 66. In such embodiments, the rotor 46 may define at least one air vent 62. The reservoir 66 may be defined 360 degrees around the axis A. In such embodiments, the at least one air vent 62 is further defined as a plurality of air vents 62, and each of the air vents 62 is fluidly coupled to the plurality of chambers 52 and is configured to exhaust air from the plurality of chambers 52. Then, during operation of the variable cam timing phaser 30, the air vents 62 all exhaust air into the reservoir 66, which is defined 360 degrees around the axis A.

[0018] In yet another embodiment, Fig.16A and 16B , the rotor 46 and the first end plate 58 define a reservoir 66. In such an embodiment, the first end plate 58 may define at least one air vent 62. In this embodiment, the first end plate 58 and the rotor 46 may be formed by a net shape process in which the components are pressed and sintered powdered metal, which typically reduces the cost of the first end plate 58 and the rotor 46, and in turn reduces the cost of the variable cam timing phaser 30.

[0019] In yet another embodiment, Fig.17A and 17B As shown in , the rotor 46 defines at least one air vent 62 and a reservoir 66 .

[0020] In another embodiment, Fig.18 As shown in , the first end plate 58 may have an end plate protrusion 74 extending away from the second end plate 60 , wherein the end plate protrusion 74 defines the reservoir 66 , and wherein the first end plate 58 defines at least one air vent 62 .

[0021] In another embodiment, Fig.19 As shown in , the rotor 46 has a rotor protrusion 76 that extends away from the second end plate 60 and defines the reservoir 66 , and the rotor 46 defines at least one air vent 62 .

[0022] It will be appreciated that in any of the embodiments of the reservoir 66 described above, the reservoir 66 may be defined 360 degrees around the axis A. It will also be appreciated that in any of the embodiments of the reservoir 66 described above, the reservoir 66 may be further defined as two reservoirs, three reservoirs, four reservoirs, or more reservoirs.

[0023] like Fig. 20As shown in , the variable cam timing phaser 30 may also include a control valve 78 that is fluidly coupled to the plurality of chambers 52 for directing hydraulic fluid to the plurality of chambers 52 to rotate the rotor 46. When present, the control valve 78 may be disposed in the housing interior 40. The control valve 78 may have a valve housing 80 that defines a valve housing interior 82, wherein a piston 84 is disposed in the valve housing interior 82. In such embodiments, the control valve 78 may be further defined as a center bolt so that the control valve 78 can secure the variable cam timing phaser 30 to the camshaft 34. In other embodiments, the control valve 78 is disposed outside the housing interior 40, such as in an oil pressure actuated (OPA) variable cam timing phaser 30.

Claims

1. A variable cam timing phaser of a variable cam timing system, wherein: The variable cam timing system includes a camshaft, and the variable cam timing phaser includes: a housing having a housing wall disposed about an axis and defining a housing interior, wherein the housing has a first housing side and a second housing side, the first housing side facing a first direction along the axis and the second housing side facing a second direction opposite to the first direction; a rotor disposed within the housing interior and movable relative to the housing, wherein the rotor has a hub and a plurality of vanes extending from the hub away from the axis toward the housing wall, and wherein the rotor and the housing define a plurality of chambers, wherein each chamber of the plurality of chambers has an advance chamber and a retard chamber; a first end plate coupled to the first housing side and further defining the plurality of chambers; a second end plate coupled to the second housing side and further defining the plurality of chambers; at least one air vent located at a center of a rotational area of ​​at least one of the housing, the rotor, the first end plate, or the second end plate; wherein a center of the rotational region is defined relative to the rotational movement of the variable cam timing phaser assembly; wherein air brought to the center of the rotational region and received in the at least one air vent during use of the variable cam timing phaser escapes hydraulic fluid, which is retained in the variable cam timing phaser; wherein the at least one air vent is fluidly coupled to the plurality of chambers and is configured to exhaust air from the plurality of chambers, and wherein the at least one air vent is defined by at least one of the rotor, the first end plate, the second end plate, and the housing; and A reservoir is fluidly coupled to the at least one air vent, wherein the reservoir is configured to hold hydraulic fluid and is configured to reduce air from being absorbed through the at least one air vent and into the plurality of chambers.

2. The variable cam timing phaser according to claim 1, wherein: The at least one air vent is at least one gap defined between at least one of the first end plate or the second end plate and the hub of the rotor.

3. The variable cam timing phaser according to claim 2, wherein: The at least one gap is in direct fluid communication with the plurality of chambers.

4. The variable cam timing phaser according to claim 1, wherein: The at least one air vent is fluidly coupled to the advance chamber.

5. The variable cam timing phaser according to claim 4, wherein: The advance chamber is further defined as a high pressure chamber, and the retard chamber is further defined as a low pressure chamber.

6. The variable cam timing phaser according to claim 1, wherein: The storage portion is configured to be at or near atmospheric pressure.

7. The variable cam timing phaser of claim 1, further comprising a ring coupled to the first end plate, wherein: The ring defines the reservoir, and wherein the first end plate defines the at least one air vent.

8. The variable cam timing phaser according to claim 7, wherein: The reservoir has a first ring cross-sectional flow area and a second ring cross-sectional flow area, and wherein the second ring cross-sectional flow area is smaller than the first ring cross-sectional flow area.

9. The variable cam timing phaser according to claim 7, wherein: The storage portion is defined 360 degrees about the axis, wherein the at least one air vent is further defined as a plurality of air vents, and wherein the plurality of air vents are fluidly coupled to the plurality of chambers and configured to exhaust air from the plurality of chambers.

10. The variable cam timing phaser of claim 1, wherein: The first end plate defines the storage portion.

11. The variable cam timing phaser of claim 10, wherein: The rotor defines the at least one air vent.

12. The variable cam timing phaser of claim 11, wherein: The storage portion is defined 360 degrees about the axis, wherein the at least one air vent is further defined as a plurality of air vents, and wherein the plurality of air vents are fluidly coupled to the plurality of chambers and configured to exhaust air from the plurality of chambers.

13. The variable cam timing phaser of claim 1, wherein: The rotor and the first end plate define the storage portion.

14. The variable cam timing phaser of claim 13, wherein: The first end plate defines the at least one air vent.

15. The variable cam timing phaser of claim 1, wherein: The rotor defines the at least one air vent and the reservoir.

16. The variable cam timing phaser of claim 1, wherein: The first end plate has an end plate protrusion extending away from the second end plate, and wherein the end plate protrusion defines the reservoir and the first end plate defines the at least one air vent.

17. The variable cam timing phaser of claim 1, wherein: The rotor has a rotor protrusion extending away from the second end plate, and wherein the rotor protrusion defines the reservoir and the rotor defines the at least one air vent.

18. The variable cam timing phaser of claim 1, wherein: The storage portion is defined 360 degrees around the axis.

19. The variable cam timing phaser of claim 1 further comprising a control valve fluidly coupled to the plurality of chambers for directing hydraulic fluid to the plurality of chambers to rotate the rotor.

20. The variable cam timing phaser of claim 1, without a check valve disposed in said at least one air vent.

21. The variable cam timing phaser of claim 1, wherein: The reservoir is fluidly coupled to the at least one air vent at its maximum radius from the axis, and the reservoir is fluidly coupled to the atmosphere at its minimum radius from the axis.

22. A variable cam timing system comprising: Camshaft; as well as A variable cam timing phaser as claimed in any one of the preceding claims.

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